The present invention relates generally to packaging of electronic components and, more particularly, to apparatus and methods that achieve compact packaging of a plurality of similar electronic components by combining the components to form an interconnected module.
Large systems of many interconnected solid state devices, such as those found in solid state data recorders, require significant numbers of similar parts to be assembled and interconnected in a high density fashion. Typically, a designer attempts to assemble as many memory components, for example, on a single printed circuit board (PCB) as possible within architectural and other constraints, thus achieving increased packing density, and increased utilization of the support or overhead electronics associated with each PCB. Increasing the number of memory devices on a single PCB also affects other overhead costs, such as structural and weight overhead associated with the PCB structure and its share of the box structure.
On one extreme, populating a PCB with a single layer of devices represents a strictly two-dimensional approach, and the highest structural and support electronics overhead cost. By contrast, stacking multiple layers of devices on the same footprint improves the structural and support electronics overhead by supporting more components in basically the same space. Although the stacking approach is a departure from a strictly two-dimensional, or area, approach, it is not a true three-dimensional, or volumetric, approach, since all interconnects between components must come down to the plane of the PCB.
Many approaches are known which stack bare die or modified packaged die to increase packing density. These approaches typically require special forms of the basic device, different from what is available as a mass-produced part. From an economic and yield perspective, it is usually best to use a mass produced component as it is available from the supplier, in a standard package and in a pre-tested state. Changing packages, or handling bare die increases cost, and increases the risk of yield reduction for the components. In a rapidly changing technological environment, the newest components are typically available only in the commercially mass produced form since the market usually consumes all that the factory can initially produce, and the manufacturer is unwilling to supply the device in any other form than that which is commercially available.
Therefore, it would be advantageous to designers of systems that require high density packaging of electronic components if a true three-dimensional approach were available to package commercially available electronic components in a high density fashion.
The present invention satisfies these needs in the art by providing apparatus and methods for high density packaging of electronic components that make use of commercially packaged and pre-tested devices in a novel grouping and three dimensional interconnection method, creating a module or block of several components, aimed at maximizing usage of structural and electronics overhead. Achieving a compact block of components allows for mounting a large number of components on a given size PCB surface, thus minimizing the number of PCB""s for a given piece of equipment, the overall size and weight of the equipment, and maximizing the usage of overhead functions on the PCB.
This approach also provides methods that can be used to assemble the components into modules such as those just described, and methods to assemble such modules onto PCB assemblies. The disclosed approach has the additional advantage that once an architecture is developed for a standard part, multiple suppliers can be used to supply the standard part, and future updates of the part can be substituted into the assembly.